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(No Model.) 2 Sheets--Sheet 1. W. G. ZEIDLBR.

APPLYING UELLULOID T0 ORGAN KEY BOARDS.

- No. 373,001. Patented Nov. 8, 1887.

"W -www- 2 Sheets-Sheet 2. W. O. ZEIDLER.

APPLYING GELLULOID T0 ORGAN KEY BOARDS.

Patented Nov. 8, 1887.

UNITED STATES PATENT OFFICE.

' WILLIAM CARL ZEIDLEB, OF TORONTO, ONTARIO, CANADA, ASSIGNOB TOAUGUSTUS NEIVELL & 00., OF CHICAGO, ILLINOIS.

APPLYING CELLULOID TO ORGAN KEY-BOARDS.

SPECIFICATION forming part of Letters Patent No. 373,001, dated November8, 1887.

' Application filed January 28, 1887. Serial No. 225,754. (No model.)

J all w/tom it may concern.-

Be it known that I, WILLIAM CARL ZEID- LER, a subject of the Queen ofGreat Britain, residing at Toronto, in the county of York and Provinceof Ontario, Dominion of Canada, have invented certain new and usefulImprovements in Applying Celluloid to Organ Key- Boards and otherArticles; and I do hereby declare the following to be a full, clear, and

to exact description of the invention, such as will enable othersskilled in the art to which it appertains to make and use the same,reference being had to the accompanying drawings, and to letters orfigures of reference marked there- 1 on, which form a part of thisspecification.

This invention relates to methods of mounting sheets of celluloid uponother materials, and to polishing the outer surface of such sheets ofcelluloid during the operation of mounting them, and it has specialreference to the applying of sheets of celluloid to wood and to thesimultaneous polishing and mounting of sheets of celluloid upon woodenorga and piano key-board blanks. The term celluloid is used herein todesignate generically celluloid proper, zylonite, chrolithium,pyroxyline, and other substances allied to celluloid proper.

It is already known to the art that celluloid, by reason ofthe camphorincorporated with it, may be rendered plastic, or even pasty orsemi-liquid, by subjecting it to heat, and that it'may be hardened againby allowing it to cool, and that by the application of great pressuresheets of the celluloid so made plastic or pasty may be partiallypressed into the surface of certain materials to cause them to adhere tosuch surface. It is also known that the surface of a sheet of celluloidmay be polo ished by pressing upon it a heated polished surface of hardmaterial. This may be accomplished by the application of only a moderatedegree of pressure and heat. Fifty pounds of pressure to the square inchand 250 Fahrenheit have been found sufficient. These two processes havebeen performed in one operationto wit, by placing a sheet of cloth orpaper and a small thin paper-like sheet of celluloid in faeeto-facecontact between the plates of a hydraulic press, the plate next thecelluloid being polished and hollow, and steam being introduced intosaid hollow plate to heat it and cause it to soften the celluloid. Onthe application of the heat and pressure the surface of the celluloid incontact with the polv ished plate becomes soft and conforms to thepolished surface. As the sheet of celluloid is thin, it becomesthoroughly plastic throughout its entire thickness. IVhile in this condition the pressure of the plates unites the cel- 6o luloid with the paperor cloth. The amount of pressure required to produce such union is,

h owever, very greatso great that only pieces of celluloid of limitedsize can be thus combined even with cloth or paper, for the reason 6 5that it is impracticable to apply the requisite pressure to relativelylarge sheets, and so great that sheets of celluloid cannot be thusmounted on wood, for the reason that the enormous pressure wouldcompress and crush the wood and render it useless.

All woods, and particularly thelight woods, are more or lessinjured whensubjected to even more than a moderate pressure. In the manufacture ofkey-boards, when excessive pressure is applied, the wood is compressed,and in most cases afterward expanded or restored by absorption ofmoisture. As each board varies more or less in its cell-structurethroughout its length, some portions are fully restored to theiroriginal thickness,while others are not. This, it will be seen, causesan uneven surface in the key-boards-a defect which renders them unfitfor the market. As most of the key-board blanks are made by gluingsmaller pieces together at their meeting edges to make the requiredsize, it follows from this cause, if from no other, that the blank is ofuneven density.

As an illustration of the great pressure re- 0 quired to unite thecelluloid to other bodies, it may be stated that a piece of celluloidmay be placed upon a larger piece of wooden board and pressed into thelatter by a heated plate until the upper surface of the celluloid and 5the surrounding surface of the board are on the same level, yet thecelluloid may be readily pulled from the wood after the plate has beenremoved.

While my process is adapted to apply sheets :00

of celluloid to wooden articles other than keyboards, I deem itsufficient to illustrate the process by setting forth its use in themanufacture of key-boards.

The method heretofore practiced in mounting celluloid upon key-boards isas follows: A blank board of suitable size and shape to form a setofkeys having been fitted to aframe bored, mortised, bushed 850., anarrow strip of celluloid, which is to constitute the polished front ofthe keys,is cemented to its front edge. This step is followed by a delayof several days to allow the cement and the celluloid, which has beensoftened by the alcohol in the cement, to become dry and hard. Thisfront is then scraped and polished, and the top sheet of celluloid isthereafter in like manner cemented to the top of the board. This step isalso followed by a long delay for drying and hardening. Next comes thescraping of the top sh eet-an arduous and careful hand task then thepolishing,which, although performed by the aid of machinery, requiresskill, time, and strengtlnbeside the employment of aquantity ofpumice-stone. A large portion of the polishing material is wasted bybeing thrown off by the motion of the machine. As the pumice-stoneisused with water,the key-board becomes wet and swollen at the rear of thecelluloid, the water often reaching and entering the back mortises andclosing them tightly upon the pins, in which case it is necessary toease them again with a handfile, and some portion of the mud ofpumice-stone and water is also left by the polisher to dry upon the woodpart of the key-board, which it is necessary to remove before the keysare separated. The scraping, filing of the mortises, and cleaning theboard is done by hand, and the polishing, although done by a machine,requires muscle and brain as well. Moreover, according to this method,from twenty to thirty days are required for drying,hardening, andsetting of the celluloid firmly upon the wood.

The extra labor and waste are a serious item in the cost of keys, andthe unavoidable delay for the drying and hardening often causes greatloss and annoyance to the organ and piano business. Special sizes andpatterns of keys are often ordered for organs, in which case a month isrequired to fill such orders. The manufacturers of keys must also keep amonths supply in the works to enable them to fill orders promptly. Evenafter waiting the length of time mentioned, the cementand celluloid arenot always thoroughly dry and hardened. Often after the boards have beenshipped to customers it is found that a slight excess of cement pressedinto t0ol-creases or soft spots or streaks in the surface of the woodwill dry and contract further and draw the celluloid over such placescloser to the wood and out of the general plane of the celluloid, thuscreating a defect which causes the purchaser to feel wronged.

By my improved method I am enabled to mount sheets of celluloid uponwood and other bodies which are destructiblc under great pressure andpolish the outer surface of the celluloid by a single short operation.This has not to my knowledge been heretofore accomplished.

Heretofore manufacturers have been unable to mount sheets of celluloidupon key-board blanks and polish them by one and the same operation. Bymy improved method the entire work of mounting, polishing, and dryingpreparatory to sawing the board into keys may be performed in from fiveto ten minutes of time.

In the accompanying drawings, Figure 1 is a view of a form of presswhich may be used for my purpose. Fig. 2 shows a portion of a key-boardblank and a sheet of celluloid to be applied to such board. Fig. 3 is anenlarged sectional View of the celluloid and a portion of the board andheated metal plate.

In the drawings, A representsahollow bedplate of the press; B, theordinary movable head or platen; O, the screw,which is provided with ahandle, D. A steam-pipe, E, leads into the hollow plate A, and awater-pipe, F, also leads into the interior of said plate. G is a pipefor the escape of steam and water from the hollow plate A. Suitablecocks are provided for each of these pipes. The upper surface of theplate A is made of steel, brass, or some other hard material capable ofreceiving a high polish, it being important that its surface he verytrue and highly polished, as any blemish in the surface of the platewould be imparted to the surface of the celluloid lying in contact withit.

The operation is as follows: The sheet of celluloid, H, is relieved ofany foreign matter adhering to the surface which is to be polished, andany over-rough places are reduced. This is done by scraping or washing.Then the other side of the sheet (that which is to be next the board) iscovered with liquid shellac, celluloid cement, (celluloid dissolved inalcohol,) or some other adhesive containing an alcoholic solvent ofcelluloid. By the time the heat is turned on the alcohol in the liquidadhesive applied to the upper surface of the celluloid has somewhatsoftened the said surface, but since alcohol is a latent solvent of thecelluloid (that is, only partially active under normal temperature andfully active under heat) the application of the heat renders the alcoholfully active and causes it to soften or liquefy the said surface to asufficient degree to establish a continuity or union between saidcelluloid and the adhesive, and the pressure causes the adhesive topenetrate and incorporate itself with the fiber of the surface of thewood. The. continued application of the heat dissipates the excess ofalcohol and reduces the adhesive and the celluloid to a form in whichthey will solidify under ordinary temperature-that is to say, when theheat is withdrawn and the adhesive, the celluloid, and the wood arecooled. By the time it will solidify under ordinary temperaturethat isto say, when the heat is withdrawn and the adhesive, the celluloid, andthe wood are cooled. The celluloid used for this purpose is necessarilyin the form of thick sheets or boards resembling heavy pasteboard. The

adhesive can, therefore,do no more than soften the upper surface of thesheet, the middle of the sheetremaining unaffected by the solvent in theadhesive. This is illustrated in Fig. 3 of the drawings, the dottedportion above representing the celluloid, H, softened by the solvent inthe adhesive, I, and the dotted portion below representing the celluloidsoftened by contact with the heated plate. The introduction of coldwater into the plate A new cools the adhesive, the celluloid, and thewood, and entirely overcomes the softening action of the heat, theordinary constituents of the celluloid being hardened and the smallproportion of alcohol remaining being rendered latent or non-solvent. Atthe same time that the heat acts upon the adhesive it also softens ormakes plastic the lower surface of the sheet of celluloid sufficientlyto allow it to be compressed to greater density and to conform to thepolished surface of the plate A. The softening action of the heated,polished surface does not extend uniformly through the entire thicknessof the sheet. While the surface of the celluloid in contact with theheated plate becomes relatively-soft, the body of the sheet remainshard, or is but slightly softened. In no case can the entire sheet besuiliciently softened to cause the surface opposite the polished heatedplate to adhere to the wood.

Experiment has demonstrated that with sheets of celluloid of thethickness used for key-boards one surface may be fused or liquefied byheat, while the opposite side is only slightly softened. Were the sheetthin like light paper it might be rendered soft through. out by theapplication of heat on one side; but in practice even the thin sheetcould not be thus rendered soft enough to allow it to ad here to wood,for the reason that such a degree of softness can only be attained bysubjecting the celluloid to a temperature but a little below itscombustion-point. To deal with celluloid under such a temperature wouldbe too dangerous to be practical.

In experimenting with small pieces it has been found that when thetemperature necessary to thus soften the sheet has been attainedit isdifficult to arrest the rise of temperature quickly enough to avoid thecombustion that would result in an explosion were the celluloidconfined. The cooling resulting from the introduction of cold water intothe plate A, after the softening of the surface of the sheet ofcelluloid, causes such sheet, as well as the adhesive, to becomethoroughly hardened and set, so that the board maybe at once removedfrom the press. The board is now found ready to be sawed into keys andshipped to customers. The celluloid is polished and hard and firmlysecured to the wood, the celluloid and cement having been entirelyrelieved of their soft orgreen condition, and the wood has not beenswollen from wetting, and the back mortises are not impaired, and thereis no refuse from polishing to be removed. Furthermore, the polishedsurface of the celluloid is now found to be of a greater density (ithaving been compressed while softened by the heat) and of a higherpolish than can be imparted to it by the old method. In the sheets ofcelluloid there frequently occur beneath the surface cells or cavities,which are cut and exposed by the old method of scrap ing and polishing,so that the sheets are made to be defective. These cavities or cells, iftoo small to be observed by the player of the instrument on which thekeys are situated, are left on the key-board and sold in that condition;but if plainly visible the tops of the defective keys are removed andnew strips of celluloid cemented in their places. The color of these newstrips is not always of exactly the same shade as the balance of theset, which of course mars the beauty of the key-board. This necessaryrepairing is often more expensive than the iirst operation of mountingthe whole sheet of celluloid. By my process such small cavities or cellsare not out or exposed. On the contrary, as already set forth, thepressure of the polished plate compresses the celluloid and increasesits density.

v Musicians have heretofore objected to celluloid key-boards because oftheir heavy, dead touch. I overcome this objection, because by myimproved method the. celluloid key-boards, by reason of their greaterdensity and higher polish, acquire the light, smooth touch of ivoryboards.

By long study and experiment and the loss of large quantities ofmaterial I have found that most of the ordinary adhesives are notadapted to my process. I am convinced that the adhesive must furnish aliquid solvent of the celluloid as well as the quality of stronglyincorporating itself with the fiber of the wood. The surface of thecelluloid must be made soft, if only to the depth of the one-thousandthpart of an inch; but such a solvent must be substantially latent underordinary temperatures. An active solvent-such as ether, for exampie-willnot serve my purpose, because the withdrawal of the heat and theapplication of the cold will not destroy the solvent action of the etherand harden and set the celluloid. On the contrary, the celluloid will besoft and green when taken from the press,in which condition it will notharden without a long period of seasoning attended by shrinking andwarping. Therefore the claims hereto appended do not embrace ether andsimilar active solvents as equivalents of alcohol.

By my processI can produce a union between the celluloid and the woodstronger than the cohesion between the fibers of the wood itself, sothat in removing the sheet the wood will be torn.

\Vhile I think it is preferable to use steam for heating the plate A, Ido not wish to confine myself strictly to the use of steam, as saidplate might be heated with agas-l'lame or otherwise.

I claim as my invention- 1. As an improvement in the art of applyingsheets of celluloid to wood, the hereindescribed process, consisting ofapplying to one side ol'the celluloid an adhesive containing alcohol orsome equivalent latent solvent of celluloid, then placing said side incontact with the wood, then placing the whole under pressure, thensubjecting it while under pressure to heat, and then restoring it tonormal temperature,substantially as shown and described.

2. As an improvement in the art of applying sheets of celluloid to wood,the hereindescribed process, consisting of applying to one side of thesheet of celluloid an adhesive containing alcohol or some equivalentlatent solvent oicellnloid, then placing said side of the celluloidagainst the wood, then placing the whole under pressure, then subjectingit to heat while under pressure, and then artificially cooling the wholeunder pressure, whereby the solvent action due to the heat is at oncedestroyed and the celluloidand adhesive are immediately hardened andset, substantially as shown and described.

3. As an improvement in the art of applying sheets of celluloid to wood,the herein-described process, consisting of applying to one side of thecelluloid an adhesive containing alcohol or some equivalent latentsolvent of celluloid, then laying said side of the celluloid against thewood, then placing the whole under pressure with the outer surface ofthe celluloid in contact with a polished metal surface, then heatingsaid polished surface su'l'iiciently to render the adjacent surface ofthe

